Artists use knives in painting for a variety of reasons, including to provide a texture to the painting. Artists traditionally have relied upon the tools developed in other industries in their painting. Unfortunately, most of these tools have been designed for specific uses in those other industries and may not be optimized for artist' use. For example, the most common artist' knives have been taken from the cake industry, where they are used to spread icing, and the construction industry, where they have been used to spread mortar.